The present invention relates to a device for distributing compressed air from a source of compressed air to a plurality of apparatus that use compressed air, and also a valve for use in the device. The invention can be applied, in particular, to a pneumatic massage apparatus comprising a massage body having a plurality of airtight chambers.
Hitherto known are pneumatic massage apparatus designed to recover, maintain and promote health of persons. Each massage apparatus comprises a massage body having a plurality of airtight chambers. The massage body is attached to the arm or the leg, and compressed air is supplied into and exhausted from the chambers sequentially, thereby to massage the arm or the leg consecutively.
Most of these massage apparatus have a compressed air-distributing device each. The compressed air distributing device is designed to distribute compressed air from a compressed air source into the airtight chambers and to exhaust the compressed air from the airtight chambers. Typically, the compressed air-distributing device comprises a fixed valve housing and a rotary valve body. The fixed valve housing has an inlet passage and a plurality of distribution passages. The distribution passages are connected to a plurality of airtight chambers, respectively. Compressed air is supplied from a compressed air source to the inlet passage. The rotary valve body has a connecting groove and an exhaust port. The connecting groove is provided to connect the inlet passage to any selected one of the distribution passages. The exhaust port is provided to exhaust air from any selected one of the distribution passages.
In the compressed air-distributing device, a spring pushes the rotary valve body onto the fixed valve (housing), setting them in a mutual surface contact. Therefore, the inlet passage of the fixed valve housing always communicates with one end of the connecting groove. The rotary valve body is rotated by an electric motor, connecting the other end of the connecting groove to the distribution passages, one after another. Compressed air is thereby supplied into the airtight chambers through the respective distribution passages, inflating the airtight chambers. When the rotary valve is further rotated, it closes all distribution passages, keeping the chambers inflated. When the rotary valve is rotated still further, the distribution passages communicate with the exhaust port. The compressed air is thereby exhausted from the airtight chambers, deflating the airtight chambers. Hence, as the rotary valve is continuously rotated in the same direction, the airtight chambers are repeatedly inflated and deflated. Selected ones of the airtight chambers can be inflated and deflated by rotating the rotary valve in one direction, alternately in the forward direction and the reverse direction within a defined rotatable angle. Alternatively, commercially available solenoid valves may be used to inflate and deflate the airtight chambers over again.
The compressed air-distributing device described above has airtight chambers into which compressed air is supplied and from which the air is exhausted, by controlling the rotation of the rotary valve body. The distribution passages of the fixed valve housing are connected to the connecting groove of the rotary valve in a predetermined order. Inevitably, the airtight chambers are inflated and deflated in a fixed order. Hence, all airtight chambers cannot be inflated or deflated at the same time, though some or all of the airtight chambers can be sequentially inflated and deflated, or only one of the airtight chambers is inflated and deflated. Further, the compressed air is likely to leak, because the fixed valve housing and the rotary valve body wear at their contacting surfaces and a gap is eventually made between them.
The flow rate of the compressed air cannot be increased since the air is supplied through the connection groove with a limited cross section. Further, each airtight chamber has a limited volume.
Moreover, commercially available solenoid valves have a narrow passage and cannot supply or exhaust the compressed air into and from the airtight chamber at a high flow rate, though they can serve to inflate and deflate the airtight chambers. In addition, the commercially available solenoid valves are expensive.
The present invention is intended to overcome the above-mentioned problems with the conventional compressed air-distributing device and the commercially available solenoid valves. One object of the present invention is to provide an inexpensive compressed air distributing valve which can supply and exhaust compressed air at a high flow rate and which excels in durability. Another object of the invention is provide an inexpensive compressed air-distributing device which can switch airtight chambers into and from which compressed air is to be supplied and exhausted, which can supply and exhaust compressed air into and from a plurality of airtight chambers at the same time, and which can supply and exhaust into and from airtight chambers at a high flow rate.
To attain the objects, a device for distributing compressed air from a compressed air source to a plurality of apparatus that use compressed air is provided according to the preset invention. The device comprises: a housing having a plurality of valve chambers, a plurality of inlet ports for connecting the valve chambers to the compressed air source, a plurality of outlet ports, each adapted to communicate with at least one of the apparatus that use compressed air, and a plurality of exhaust ports communicating with outside the device; a plurality of spherical valve bodies movably provided in the valve chambers, respectively, each for closing one inlet port and one exhaust port; a plurality of shafts extending from the valve bodies, respectively, each shaft having an end portion passing through one exhaust port and protruding from the housing; a plurality of electromagnetic actuators coupled to the end portions of the shafts, respectively, each designed to move one valve body between an air-supplying position where the valve body closes the exhaust port and connecting the inlet port and the outlet port and an air-exhausting position where the valve body closes inlet port and connecting the outlet port and the exhaust port.
In the compressed air distributing device, each of the valve bodies constitutes a three-way valve, together with one valve chamber. The three-way valves are driven by the electromagnetic actuators, respectively, to connect the outlet ports to either the inlet ports or the exhaust ports. Thus, each three-way valve is controlled independently of any other three-way valve. Hence, the device can supply and exhaust compressed air from any selected ones of the apparatuses at the same time.
Since the valve bodies are spherical, they occupy only a small space in the respective valve chambers. A large air passage is therefore provided in each valve chamber. The three-way valves are extremely simple in structure and can be inexpensive. Incorporating inexpensive valves, the compressed air-distributing device can be manufactured at low cost.
It is desired that each of the electromagnetic actuators have a movable member, an electromagnet for moving the movable member and a spring biasing the movable member. Also is it desired that each of the valve bodies remain at one of the air-supplying position and air-exhausting position while no electric current is supplied to the electromagnet.
Further, it is desired that the device should further comprise a header extending parallel to the housing and adapted to be connected to the compressed air source, and that the inlet ports should be connected by the header to the compressed air source.
Furthermore, it is desired that the end portions of the shafts be pivotally coupled to the movable members of the electromagnetic actuators, respectively. If the end portions are so coupled to the movable members, each valve body can reliably close the inlet port and the exhaust port even if its axis is not aligned with that of the inlet port or exhaust port.
It is also desired that each valve body have a surface portion made of elastic material. If the valve body has such a surface portion, it will provide an appropriate sealing surface.
Furthermore, a valve is provided according to the invention, for use in a device designed to distribute compressed air from a compressed air source to a plurality of apparatus that use compressed air. The valve comprises: a housing having a valve chamber, a inlet port for connecting the valve chamber to the compressed air source, an outlet port adapted to communicate with at least one of the apparatus that use compressed air, and an exhaust port communicating with outside the device; a spherical valve body movably provided in the valve chamber, each for closing one inlet port and one exhaust port; a shaft extending from the valve body and having an end portion passing through the exhaust port and protruding from the housing; an electromagnetic actuator coupled to the end portion of the shaft and designed to move the valve body between an air supplying position where the valve body closes the exhaust port and connecting the inlet port and the outlet port and an air-exhausting position where the valve body closes inlet port and connecting the outlet port and the exhaust port.
It is desired that the electromagnetic actuator have a movable member, an electromagnet for moving the movable member and a spring biasing the movable member. Also is it desired that the valve body remain at one of the air-supplying position and air-exhausting position while no electric current is supplied to the electromagnet.
Furthermore, it is desired that the end portion of the shaft be pivotally coupled to the movable member of the electromagnetic actuator. If the end portion is so coupled to the movable member, the valve body can reliably close the inlet port and the exhaust port even if its axis is not aligned with that of the inlet port or exhaust port.
It is also desired that the valve body have a surface layer made of elastic material. If the valve body has such a surface layer, it will have an appropriate sealing surface.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The object and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.